Preparation, Raman spectroscopy, surface morphology and optical properties of TiPcCl₂ nanostructured films: thickness effect

Phthalocyanines are of a broad interest in photovoltaic applications. In this study, films of titanium-phthalocyanine-chloride (TiPcCl₂) were prepared by the thermal evaporation method. The molecular structure was studied by a Raman spectrometer, showing a match between the spectra of the powder and the prepared films. The films' surface was examined by the atomic force microscope, revealing grain size and surface roughness of TiPcCl₂ thin films to be 223 and 41 nm, respectively, for a 100 nm thickness. The energy gap was determined to be 1.5 eV, with no observable effect by the thickness change. Additionally, the linear and nonlinear optical constants were calculated from reflectance and transmittance measurements. The values of third nonlinear susceptibility are in order of 10^–12 esu, which is compatible with other phthalocyanines. The nonlinear optical constants indicate that TiPcCl₂ films could also be used for optical laser limiters.